Blocker type clutch



P ORR BLOCKER TYPE CLUTCH Filed Dec 22 1948 Aug. 19, 1952 I Patented Aug. 19, 1952 IBLOCKERTYPE CLUTCH:

Balmer Orr, Muncie, Ind., assignolt to Bor Warner Corporation, Chicago, 111 a corpora tion of Illinois Application December 22, 19, 18;-SerialiNoifififiS, f

This; invention relates to, transmissions and more particularly to a: mechanical power transmission incorporating among other improvements a. novel synchronizer mechanism whereby. the

power transmittingmembers; of the transmis- I equal sionmay becaused' to'rotate at substantially speeds-prior to being intermeshed, i

- Intransmissions of the'type employingblocker synchronizers, it i's'necessary thatthere be a frictional contact between the friction faceof the synchronizer'drum and the friction face of the companion member, associated: with j one of the, gears; to' insure draggingthe drum substantially to the limit of its angular adjustability on he-splinedshaftj on which the drum is pivoted.

This displacement ofthe drum provides the requiredinitial alignment of the blocker. faces whereby; the drum may be pressed into contact with the companion member with sufiicient force to; establish? synchronization. As is well known, once synchronization is established, the blocker faces move out of alignment and the frictional contact between the drum and the companion member is substantially removed.

Theinitial alignment of the blocker faces is usually. established by the drag of the oil film between the friction surfaces of' the companion member and; the synchronizer drum. In some cases; however, the. dra'g'of the oil filmjbetween thefriotion surfaces is inadequate to provide the required initial rotation of the synchromizer drum without addedraxial-pressure; Thus,forexample, because; of; variations inthe thickness of the oil film duetothe variation of the oilviscosity and other film cham'cteristicsof the oil in use, the drag provi'ded I by the oil is not .of uniform value atja-lltimes and; under certain conditions,.-particularlyrwh'en -hot, may: be wholly inadequate.

Under 'SUOhiCOIIdlUiOIlS, itis possible for the block- ,enfacesmotto be aligned as the shifting. mechanismisgoperatedq and axial pressure is to be applied: to the synchronizer drum to cause. it to engage its companion, member. Under-these conditions; nopressure is applied to the synch'rnnizer drum,;-'consequently, there is no synchronization and the gears clash. x

In; orderto-avoid such erratic operation in frictional engagement,

blockertype.synchronizers, one practice has been v the synchronizer.

while. not. gr.eat, represents an undesirable power lossv andiinvolyes cone stant wear, thereby reducing thev useful life of In. order to. overcome these objectionable characteristics, it has been suggested that. a resilient member be providedlwhich .is-engaged only during: the initialshifting, move;- ment toproduce the requisite drag. With this latter typeof arrangement, the, requisite drag is only established for a moment, insteadofbeing continually presenttas with the, constant pres:- sure spring I v For this'reason, thelatter-arrange: ment is preferred in; principle. Howevenheretofore it has been, foundin practicethat itis extremely difficult to -design a transmissionfin which the synchronizer drag is established only intermittently, asrequired, and yet the syn.- chro nizer arrangement will consistently provide the-required degree of axial pressure, without re-.- sortingto expensive and unduly complicated arrangements. v

An object ofthe. present. invention is toprop videa. new and improved transmission and par.- ticularlya synchronizer mechanism capable of consistent and: eifective operation.

A 1 further object of the present inventionisto provide a transmission having a blocker type syn,- chronizer; arranged" to consistently provide the drag necessary to: establish the'initial alignment 30 of the synchronizer blookerfaces.

yention, the synchronizer drum is providedwith a pluralityofi axially extending blocker stubs: which qare adapted to engage the chamfered faces-of the entrances of' corresponding, axially extending a-pertures-formedinthe shiftable gear to provide blocker action; the stubs entering the; apertures and; relieving the pressure on the synchronizing surfacesonce synchronization is established. In order to insure suiiicient: dragto cause-1 the syn chronizer drum to be angularly+ displacedtozthe limit ,of; its rotatabilitiionthe supporting splined shaft-and thereby to-causetheendsof thestubsi-to seat initially'o-n the chamferedfaces; a- -resilient memberis. associat-ed'with: each aperture Ofi. the shiftable gear and; partially obstructs the entrance to theaperture. The resilientmember is initially engaged by a camsurface formed: adj acent the-terminal,rend ofthe; associated-stuband the resilient member isso positioned-with respect to the vblockerfacesas. tocause the synchronizer drum to be pressed intocontact withits companion member prior to the stubs touching the blocker facesat the entrances of the apertures: This-inrtial contact -,between the. synchronizing; surfaces is sufiicient to causejzl-re ring-toirotaterelativelyito the gear and to establish the desired alignment of the blocker faces and the stubs. Continued shifting movement by the operator causes the resilient members to be deformed and to ride over the cam surfaces on the blocker stubs and then the usual blocker action takes place.

Other objects and advantages of the present invention will be apparent from the following detailed description taken in conjunction with the drawings wherein: 7

Fig. 1 is a fragmentary, axial, sectional viev of a transmission incorporating a synchronizer constructed in accordance with the invention;

Fig. 2 is a sectional view taken along the line 2-2 of Fig. 1;

Fig. 3 is an enlarged, sectional view taken along r the line 3-3 of Fig. 1 showing the relative positions of the blocker faces during alignment; and;

Fig 4 is an enlarged, detailed view illustrating the, configuration of the end of the blocker stub and mode of engagement with the spring member carried by the shiftable gear.

Referring now to the drawings and particu thereto a larg driving gear H which is axially shiftableon the'shaft it! by suitable means such "as a shiftingfork (not shown). The driving gear. ll'lias integrally'formed therewith on the left side thereof a two sector, hub gear l2 comprising one of two positive clutch members, and by shiftingthe driving gear II to the'left, the hub gear l2 may be caused to engage the teeth of an internal gear [3 comprising the second of the twopositive clutch members. The gear l3 is'integ'rally formed with a driven gear [4 having external teeth l5 which may be meshed with a third gear (not shown). The driven gear I4 "is i'otatablysupported on the main shaft If] by bearing assembly I] and isprevented'from moving axially of the shaft 19 by retaining rings .l8 positioned 'at either end of the bearing assembly l'l andjsuitable splitrings l9 carried by {the shaft l0. 3

1 In order tosynchronize the rotational speed of the driving gear II and the gear l4 so that the teeth of the'hub gear [2 will not clash as they are meshed-with the internal gear 13, a

In accordance with the present invention, blocker action is provided by a plurality of stub shafts 21, these stub shafts extending to the right, as viewed in Fig. 1 and being rigidly secured to or integrally formed with the right side of the synchronizer drum 20. In the embodiment illustrated, three blocker .stubs are provided; however, it will be understood that a greater or lesser number may be employed as required. These blocker stubs are arranged to engage at their terminal ends chamfered, annular blocker faces 28 formed at the left ends of correspondingly positioned, axially extending apertures 29 formed in the driving gear ll.

' As more clearly shown in Fig. 3, the terminal end of each stub is Wedge shaped to provide a pair of bevel faces 3|, the bevel angle corresponding to the chamfer angle of the faces 28 of the apertures 29. Two bevel faces 3! are provided at the terminal end of the blocker stubs since synchronization is provided in either direction of rotation of the gear I I relatively to the gear l4. e

- At theiristant'that the gear H is shifted toward the gear !4, it will be appreciated that the terminal ends of the blocker stub may be aligned with either set of the blocker faces of the apertures 29 so that a suitable blocking engagement is had. In such case no problem of alignment-is present. However, it is'possible that the synchronizer drum 20'will be rotated slightly from either limit of its travel with respect to the shaft It and the blocker faces then will not be completely aligned and inadequate frictional engagement will be had to establish the necessary synchronization. Itis also possible that the blocker faces and the stubs will not be aligned at all, that V is to say, the stubs will be aligned with the apersynchronizerdrum 20 is provided'and is positioned between the gear H and the gear M, being piloted on the splined portion of the shaft '10 by a pair o-foppositely disposed, inwardly extending spokes 2] integrally formed with the corresponding splined recesses 23 formed in opposite sides or theperiphery of the shaft, thereby providing a limited freedom of movement so that the drum 20 may be rotated slightly with respect to the shaft [0, this angular adjustability being necessaryto enable the required alignment of the blocker faces, as will be more 7' The synchronizer drum 20 has an internally disposed ring 2 3 which provides, in conventional manner, an in- 'fully' described hereinafter.

ternal conical friction face adapted to engage anexternal conical friction face 25 of the gear [4, as is clearly shown in Fig. 1.

tures 29 and pass into these apertures as soon as the gear II is shifted. Under'this circumstance, shifting the gear H toward the gearM provides no blocker action whatever. These possible erratic alignments of the blocker faces 28 and the terminal ends of the blocker stubs are wholly avoided in accordance with the present invention by providing rod-shaped springs 32 which extend across each of the apertures 29, as clearly shown in Fig. 2, and obstruct the'entrance to the apertures. Each spring 32 issupported in position by a pair of spaced lugs one ofwhich is positioned on either side of the aperture-Z9 and both of which are located slightly outside of the chamfered faces 28 in such manner that the cross portion of the spring 32 ispositioned slightly outside the axis, in 'a'radial direction, of the associated aperture 29, the spring 32 lying in'efiect on a chord of. the circular aperture. The ends of the springs are wrapped around the lugs to secure them thereto so that upon deflection of the cross portion of the spring by the blocker'stub, suitable resistance to deflection is afforded.

As shown in Figs. 1 and 4, the upper side of the terminal end of each stub 2'! is shaped to cooperate with the spring 32; thus the terminal end of each' stub has provided thereon a sharply beveled portion 35, which leads to a dwell portion 36, formed on the upper side of the stub and hav ing at its left end an upwardly curved camsurface 3'! terminating at the left in the upper surface of the stub. The springs 32 and the terminal ends of the stubs 21, particularly the cam surfaces 31 thereof, cooperate to insure that upon -the initial'shifting'movement of the gear H toward the gear M, a sufficient pressure engage- 'ment is effected between the friction faces of the synchronizer ring and the gear 14 to cause the accents drum wto rotate. the: stubs-.211: with: respect: to theapertures: 2'! to. effectlaligmnentb .1

To facilitate: understanding: Offlthibi invention, the: shifting of the gear" tl: towacdthezgeamtd will be described in several stages-2 In first stage;- the synchronivei! drum 21k is ridinglnosely on the-shaft 11c and the te'rmimazlz en'dsz oft .thestub shafts are:v slightly spaced from the springs; 32;. a split ri-ng 3'4; fixed td-the shaft I20 establishing the limit: of: rightward movement of the: arm 20. and being'so located: that whemthe sides'of the spokes? 2t bear against the ring 34;. iszsubrstantially no frictional. engagementbetween. the conical friction surfaces Off the: synchronizer. The: synchronizer' drum. 202v of: ccursigrdtates: with the shaft; rm beyond: the.- limits otits angular: adf: instability therecna.

Imth'e second: stage of;'theeshiftingiopemation, as: the gear I: I: is shifted; toward: the: gear: the sharply beveled; surfaces 352 at the terminal; ends of the stub shafts 212 engage; the springs 32: brief-'- Ly; asxshowir in Fig.1, the beveled surfaces senving only to facilitate and to; guide thezmovemenii'of the springs 32'. ontorthe' dwelt. porticns tfiof each of the stubshafts. thus' giving the operator. an indicatiom due to? increased resistance to" movemenathatthe stubs have been reached; hrthe third stage of the shifting. movement; the. cross portions. of: the springs 32",.- as: shown: Fig; 4

we brought to bear againstithe surfaces. 3

formed on: the stubs 21 and. continued: shifting movement presses the synchronizer ring." 2!. into engagement with the conical surface 25, thereby dragging the drum 2!! to the limit of its angular adjustability on the shaft and aligning one set of the bevel faces 31- at the; terminal ends of the blocker stubs with: the corresponding chamfered faces 28 of the gear. The position of the cam surfaces 31 of each blocker stub 21 is so selected with reference to the location of the associated spring 32 and the location of the chamfered faces 28- that nc-engagement" is hadbetween the cham-feredfaces 28- and the beveled faces 3 i of the terminal ends of" the blocker stubs during this third stage-ofthe shifting movement; Thus, when the springs 32 are brought to bear against the initial portion of the cam surfaces 31, these cam surfaces 31 provide in combination with the resistance to deflection of the springs 32 the requisite pressure of engagement of the synchronizer ring 24 and the friction face 25. This engagement of the synchronizer ring 24, with the conical surface 25, in producing the aforementioned dragging action, causes the drum 2!) to rotate with respect to the shaft ID, the direction of rotation depending on the direction of rotation of the gear M, or its speed of rotation relatively to that of the shaft ID. The drum rotates to the limit of its adjustability as established by the width of the splined grooves 23 formed in the splined shaft l0 and that of the cooperating spokes 2|, thereby aligning bevel faces 3| at the terminal ends of the blocker stubs 21 with the corresponding chamfered faces 28 on one side of the apertures 29.

In the fourth stage of the shifting movement, as the gear I I is shifted still farther to the left, the blocker faces 28 engage the bevel faces 3| and the usual blocker action ensues. The gear [4 is thereby synchronized with the rotation of the gear II and when this occurs, as is well known, the setting force developed by the differential rotation of the synchronizer elements disappears, permitting the blocker faces to break away. The stubs 21 are then cammed away from the blocker: faces 2& and become alignedsiwith:

the. apertures 2:9. In. the final'stage; continued shifting; movement of. the 882;!7Hi10'3fl1868ith8 stubs; 2.1: ito= be; received inthe apertures; 29; at the sametime the hubigear t2 on thegean-I I; meshes the? internal: ring gear 53 integrally formed with: the: gear: M establishing: a positive driving connectionbetween".theseztwa gcars Where: herein the" various parts of. thetrans mission havebeen-'- referredv to as being; located. in V first. gear rota-table: with said: driven" shaftwand axially shiftable thereon; a. second gear. rotatableon said driven: shaft and: adaptedvtowbe-engaged by said first gear; said second: gearbeingzh eld-in fixed axial location on said driven shaft,v a. sym- 'chronizer drum: splined on. said. driven-shaft: and capable of limited angular rotation. withirespect thereto, and located between the first gear and the second gear, an external. tri'ction' surface on said second gear. adapted to be irrationally engaged .by 'a corresponding: internali' friction sue face: on the: synchronizer' drum; and means for rotating the synchronizerdrumto theilimitcf its angular adjustability on the driven shaft prior to; the first gear being: shifted intoengagement with the second gear; said means comprising tension spring carried by the first gear' and a blocker stubcarried by said s-ynch-ronizer drum and? arranged so as to engage the spri W first gear is shifted v tow'ard the second gear to provide an initial engagement between thesynchronizer drum: and the friction surface oh the second gear whereby the synchronizes drum is rotated to the limit of its angular adjustability on the driven shaft and synchronization between the gears is effected, said first gear having an axially extending aperture therethrough, the spring being deflected by said blocker stub and the blocker stub passing through said aperture upon continued shifting movement of thefirst gear after synchronization between the gears is effected. I

2. A synchronizer drum having a blocker stub rigidly secured thereto, the terminal end of said blocker stub being wedge-shaped to provide a pair of beveled blocker faces, a third bevel face being provided at the terminal end of said blocker stub and extending in a plane lying generally at right angles to said pair of bevel faces, a cam surface formed adjacent the terminal ends of said blocker stub and an intermediate dwell portion connecting said cam surface and said third bevel surface.

3. A transmission including a driven shaft, a first gear rotatable with said driven shaft and axially shiftable thereon, a second gear rotatable on said driven shaft and adapted to be engaged by said first gear, a synchronizer drum splined on said driven shaft and capable of limited angular rotation with respect thereto, and disposed between said two gears for establishing synchronization therebetween, a friction surface on said second gear being frictionally engaged by the '7 synch'ronizer drumto eifect synchronization; at least'one blocker stub fixed to said synchronizer drum and extending therefrom toward said first gear, said first gear having a correspondingly positioned aperture formed therein to receive the blocker stub, and a tension spring located so as toobstruct said aperture, said spring being engageable by the terminal portion of said blocker stubi'during initial shifting movement of the first gear toward the second gear to provide an initial pressure engagement between the synchronizer drum and the friction 'surfacelon the second gear thereby torotate the synchronizer drum to the,

limit of 'its angular movement on the driven shaft to thereby effect synchronization between f-the gears, said spring yielding upon synchronization of the gears andthe aperture permitting the blocker stub to pass therethrough'to thereby permit engagement of the gears upon further shifting movement of the first gear.

- 4. A transmission according to'claim 3 wherein said aperture has a chamfered entrance providing chamfered blocker faces and the terminal end of saidblocker stub is wedge-shaped to provide a pair of correspondingly beveled blocker faces,

and the blocker stub has a cam surface formed adjacent the terminal end and arranged to engage theresilient means carried by the first gear prior to engagement .being effected between either of the chamfered' blocker faces and either of the bevel blocker faces. 7

'5. A transmission including a driven shaft, .a first gear rotatable with said driven shaft and axially 'shiftable thereon, a second geargrotatable on said driven shaft and adapted to be engaged by said shiftable first gear, a synchronizer drum splined for limited rotation on said driven shaft and disposed between said two gears for establishing synchronization therebetween, a friction surface on said second gear being frictionally engaged by thesynchronizer drum to effect synchronization, at least one-blocker stub fixed to i said synchronizer drum and'extending therefrom toward said first gear, said first gear having a correspondingly positioned aperture formed 8 v therein'and arranged to receive the blockerstub upon said firstgear meshing with said second gear a wire-like tension'spring extending across the entrance to said aperture and located so as to partially obstruct said aperture, said spring being engagable by the terminal portion of said blocker stub and placed under tension during initial shifting movement of the first gear toward the second gear-to provide an initial pressure engagement between the synchronizer drumand the friction surface onithe second gear thereby to rotate the syn'chronizer drum to the limit of its angular movement onthe driven shaft;

6. Atransmission according to claim 5 wherein the entrance tosaidaperture is chamfered to provide an inclined surface, and the terminal end of said blocker stub is correspondingly inclined to provide a cooperating blocker face and the blocker'stub has a "cam surface formed'thereon intermediate the terminal end thereof and the synchronizer drum and arranged to engage the spring carried by the first gear during initial shifting movement ofthe gear, the cam surface being so.located with respectrto the inclined blocker face at the terminal end of the stub and the inclined surface at the entrance to the aperture in the gear being solocated with respect to the cam surface engaging portion of the wire spring that'when the wire spring bears against the cam surface the blocker surface at the terminal end of the blocker stub does not engage the inclined surface at the entrance ,of the aperture. I p v i I PALMER ORR.

REFERENCES CITED The following references are of record in the file of this patent:

UN TED STATES PATENTS 2,397,344 Fishburn Mar. 26, 1946 

